Numerical study on ESR by making use of Wiener-Khinchin relation in time domain

TL;DR

This paper introduces a novel numerical method for calculating ESR spectra in quantum spin systems at finite temperatures, utilizing the Wiener-Khinchin theorem to improve computational efficiency over traditional approaches.

Contribution

The paper proposes a new method based on the Wiener-Khinchin relation to compute ESR spectra from magnetization time evolution, extending previous Fourier transform techniques.

Findings

Efficient numerical calculation of ESR spectra at finite temperatures.

Applicable to larger spin systems than traditional methods.

Demonstrates improved computational performance.

Abstract

To evaluate ESR spectrum at finite temperatures for specified spatial configurations of spins is very important issue to study quantum spin systems. Although a direct numerical estimation of the Kubo formula provides exact data, the application is limited to small size of the system because of the restriction of the computer capacity. The method of the Fourier transform of the autocorrelation function improved the restriction. As an extension of the method, we propose a new method for numerical calculation of the ESR spectrum from the time evolution of the magnetization by making use of the Wiener-Khinchin theorem.